Kerb and drainage installation and method and apparatus for fabrication thereof

ABSTRACT

A combined curb and drainage installation is formed as a slip-formed or extruded product, or else as a number of discrete pre-cast blocks, suitably of concrete, and has a curb overhang portion  6  which overhangs an opening of an inlet  2  which leads directly to a drainage duct  3  below. Water readily flows into the duct via the inlet, but cycle tires are prevented from entering the inlet by the curb overhang portion  6.

[0001] The present invention relates to a combined curb and drainage installation and to a method of its fabrication. Such installations are often used in motorway construction and for other major roads, but are suitable for edging of any road of track surface in which both a curb and drainage are required.

[0002] In particular, the invention has application in providing the curb and the drainage needed for such surfaces in a single installation and thus a cost-effective simple alternative to the separate construction of curb and drainage systems.

[0003] Curbs have generally been made from separate blocks of stone, concrete or the like laid along the edge of the pavement or other walking surface for pedestrians. The drainage system traditionally provided in such an arrangement is a separate duct underneath the road surface and/or pavement with entrances to the duct being provided in the form of grids usually of metal situated periodically along the road surface adjacent to the curb.

[0004] Such traditional arrangements may be time consuming to lay and difficult to repair.

[0005] Combined curb and drainage systems have been proposed. For example, GB 2027779 discloses hollow curb drainage units wherein a drainage channel is defined within a block having opposed communicating apertures for the passage of water along the length of such blocks laid end to end. Each block includes periodic, spaced front openings acting as inlets for drainage water. GB 1591332 discloses a combined drainage channel and curb with similar, generally vertically facing inlets spaced along its length, leading to a central channel.

[0006] These combined systems have the disadvantage that they cannot be produced by the slip-forming or extrusion processes, because it is impossible, or at least very difficult, to produce a slip-formed or extruded product having periodic openings along its length. Slip-forming and extrusion are preferred methods of fabrication, being cost-effective and simple.

[0007] In the slip-forming technique the cementitious material is compacted, and a mould is caused to pass over it to apply the desired profile to the material. In the extrusion technique, the cementitious material is forced under pressure through an extrusion head or mould, from which the material emerges in the required shape.

[0008] Some known systems are produced by the slip-form process. These are drains having a continuous longitudinally extending slot above, and leading to, a drainage duct (“slot drains”). The drains and hence the inlet slots must cope with rainwater and a wider slot offers better (faster) drainage. However, drains with a sufficiently wide slot to cope with normal drainage requirements can present a hazard for cyclists, whose bicycle wheels may ride into and become trapped in the slot. This is especially the case if the slot or the opening to it is substantially vertical.

[0009] For this reason bridging pieces must be positioned at regular intervals across the inlet to avoid narrow wheels or other objects falling into the inlet and possibly becoming wedged therein. Such bridging pieces, and indeed any other parts positioned to divide an inlet slot into sections, have the disadvantage that they may catch debris carried by drainage water and lead to blockage of the inlets. More importantly, their inclusion means that the drain cannot be manufactured in a simple unitary slip-form process. Rather, the additional parts must be positioned within the drain by hand during the fabrication process, thereby eroding some of the advantage of the slip-form or extrusion process.

[0010] It is an object of the present invention to overcome or at least mitigate some of the disadvantages in the prior art.

[0011] According to a first aspect of the present invention there is provided a combined curb and drainage installation comprising a drainage inlet having a substantially downwardly directed opening and leading to a longitudinal drainage duct, and a curb adjacent to the opening, wherein the curb has an overhang portion which at least partly overhangs the opening.

[0012] The invention allows construction of a cost-effective curb and drainage installation, without danger to cyclists, which does not require bridging pieces or other parts dividing the inlet into sections. The overhang of the curb acts to ensure that the installation is safe for cyclists since it prevents the wheels of a bicycle from entering the opening, without in any way restricting the flow of water into the opening.

[0013] The expression “substantially downwardly directed” is to be taken to include any opening, the direction of which has a vertical component.

[0014] The opening of the inlet may be at any preferred angle to the vertical to allow drainage-water entry. It is preferably directed vertically.

[0015] The inlet may have any suitable shape. Preferably, the inlet is a longitudinally extending slot. The orientation of the inlet may be any that provides drainage for the passage of drainage water. The inlet should thus at least slope downwardly for drainage purposes and preferably extends substantially vertically. The inlet preferably forms a simple vertical path directly between its opening and an entrance into the drainage duct. This feature facilitates fast drainage and lessens the likelihood of blockage due to matter such as leaves or debris being trapped in the inlet. The inlet may be wider at its lower extent than at its upper extent. This feature may also help to reduce the likelihood of the inlet becoming blocked.

[0016] Any suitable length of the curb overhang portion may be provided over the opening. Preferably, the curb projects over more than half of the opening. In one preferred embodiment, the curb projects over substantially the full horizontal extent of the inlet opening. The overhang may even project beyond the inlet opening towards the road surface, for example where this may give an added safety margin for bicycle wheels.

[0017] Any suitable shape may be used for the overhang, but it is preferably constant along the installation for simplicity of fabrication and cleaning. In particular, the overhang may be rounded in vertical cross section to form a continuous smooth lip. The lip may be curved over its entire projecting surface or it may have a combination of curved and straight edges, provided for example by rounded edges of an approximately rectangular section.

[0018] The installation may further comprise a run-off surface opposite to the curb and sloping downwardly towards the inlet to facilitate the entry of drainage water. The run-off surface may be at about 5 to 30° to the horizontal in one preferred embodiment. The upper edge of the surface may be approximately level with the bottom of the curb overhang portion.

[0019] The duct may be of any suitable size and shape. In one preferred embodiment the duct is of substantially circular cross section and has a diameter of approximately 250 mm.

[0020] The installation as a whole is preferably approximately rectangular in vertical cross section, with an approximately centrally positioned duct; the inlet leading directly to the centre of the duct.

[0021] The installation is preferably formed of concrete or other suitable material. The installation is preferably of substantially constant shape and size over its entire length and may, for example comprise an extrusion or slip-formed product.

[0022] In a further aspect of the present invention there is provided a method of producing a combined curb and drainage installation comprising the single step of slip-forming or extruding the curb and drainage installation in situ; wherein a curb overhang portion is formed which projects at least partly over a substantially downwardly extending opening to an inlet channel.

[0023] The method according to the invention is particularly advantageous because it does not require further steps beyond simple slip-forming or extrusion. Prior constructions may require the insertion of separate parts along the installation, whereas the curb and drainage installation made according to the present invention preferably has a substantially identical cross section along its entire longitudinal extent.

[0024] The installation is preferably slip-formed or extruded around a forming member to provide the longitudinal drainage duct. The forming member may, for example, be an inflatable or collapsible tube which is inflated during forming of the installation. Inflation of the tube, where provided, is normally by air, for example from a compressor.

[0025] The invention also includes apparatus for producing a combined curb and drainage installation, the installation having a curb overhang portion which projects at least partly over a substantially downwardly extending opening to an inlet channel, the apparatus comprising a mould, the shape of which is so as to produce the installation with the overhang portion. The apparatus may further include a forming member around which the installation is slip-formed or extruded to produce a longitudinal drainage duct. The forming member is preferably an inflatable plastics tube, however, it may alternatively be a hollow or solid rigid body. The apparatus may further comprise an end clamp to seal air in the plastic tube, and support pieces for the plastic tube which is supported in situ along the roadside.

[0026] An embodiment of the invention will now be described, by way of example, with reference to the accompanying drawings, in which:

[0027]FIG. 1 is a vertical cross section through a curb and drainage installation according to the prior art;

[0028]FIG. 2 is a vertical cross section through a further prior art drainage installation;

[0029]FIG. 3 is a vertical cross section through a curb and drainage installation according to a preferred embodiment of the present invention;

[0030]FIG. 4 is a diagrammatic representation in vertical cross section of the use of an installation according to a preferred embodiment of the invention; and

[0031]FIG. 5 is a diagrammatic representation of the forming process for an installation according to a preferred embodiment.

[0032]FIGS. 1 and 2 show prior art constructions which are suitable for motorway use and have slots sufficiently wide for normal drainage purposes. For the safety of cyclists, both of these must be used with bridging pieces or spacers positioned regularly along the full extent of the installation if they are to be adapted for normal road use. The prior art installations 1 each include a vertical slot 2 leading to a longitudinal drainage duct 3. The installation shown in FIG. 1 also provides a curb 4 and a bridging piece 5 is shown in position in the slot.

[0033]FIG. 3 shows a preferred embodiment of the invention. Like parts are numbered with like reference numerals as for the prior art. FIG. 3 shows the curb overhang portion 6. In this embodiment, it is formed by a rounded lip which projects across substantially the whole horizontal extent of the simple vertical inlet 2. The installation also provides a run-off surface 7 sloping towards the inlet.

[0034]FIG. 4 demonstrates the use of the overhang. If a bicycle wheel 8 wanders off the road surface 9, for example due to heavy traffic or inattentive cycling, it cannot enter the inlet, as the overhang portion prevents this.

[0035] Although the invention has been illustrated by a single embodiment, the skilled addressee will readily appreciate the possible modifications. For example, the shapes and orientation of various parts of the installation may differ from the shown, as long as they fulfill their function. For example, the slot may slope downwardly, (preferably away from the road surface) rather than being vertical and the run-off surface may be horizontal.

[0036] Furthermore, although the installation has been described above as a slip-formed or extruded product, it could comprise discrete blocks laid end to end.

[0037]FIG. 5 shows a simplified sketch of the fabrication process, in which a plastic inflated tube 10 is shown in situ within the newly formed installation when a slip form or extrusion mould 11 has just slip-formed or extruded a section of the installation. The mould 11 is suspended from a larger support apparatus and fed from about with concrete or other suitable material. The plastic former tube 10 is supported above the ground by support devices along its length, or else is simply laid to rest on the ground, and inflated before slip-forming or extrusion begins. After slip-forming or extrusion, the inflation is maintained for some time to allow the concrete or other material to set, after which the tube is deflated and removed. The tube 10 is shown here in a partially deflated state.

REFERENCE NUMERALS

[0038]1. Installation

[0039]2. Inlet

[0040]3. Longitudinal drainage duct

[0041]4. Curb

[0042]5. Bridging piece

[0043]6. Curb overhang

[0044]7. Run-off surface

[0045]8. Bicycle wheel

[0046]9. Road surface

[0047]10. Former tube

[0048]11. Mould 

1. A combined curb and drainage installation, comprising a drainage inlet, having a substantially downwardly directed opening and leading to a longitudinal drainage duct, and a curb adjacent to the opening, wherein the curb has an overhanging portion, which at least partly overhangs the opening.
 2. An installation according to claim 1, wherein the opening is substantially vertical.
 3. An installation according to claim 1, wherein the inlet comprises a longitudinally extending slot.
 4. An installation according to claim 1, wherein the overhanging portion of the curb extends over more than half of the width of the opening.
 5. An installation according to claim 1, wherein the overhanging portion of the curb extends over substantially the entire width of the opening.
 6. An installation according to claim 1, comprising a slip-formed or extruded product.
 7. An installation according to claim 1, comprising a plurality of discrete, pre formed blocks laid end-to-end.
 8. A method of producing a combined curb and drainage installation, the method comprising arranging end-to-end a plurality of pre-formed blocks as claimed in claim
 7. 9. A method of producing a combined curb and drainage installation comprising the single step of slip-forming or extruding the curb and drainage installation together in situ, wherein a curb overhang portion is formed which projects at least partly over a substantially downwardly extending opening to an inlet leading to a longitudinally extending drainage slot.
 10. A method according to claim 9, wherein the installation is slip-formed or extruded around a forming member which forms the drainage duct.
 11. Apparatus for fabricating a combined curb and drainage installation, the installation having a curb overhang portion which projects at least partly over a substantially downwardly extending opening to an inlet, which inlet leads to a longitudinally extending drainage duct, the apparatus comprising a slip-forming mould or extrusion head, the shape of which is such as to form the installation with the curb overhang portion.
 12. Apparatus according to claim 11, further comprising a forming member around which the installation is slip-formed or extruded to form the drainage duct. 